A reconfigurable antenna comprises an array of interconnected gas enclosures, each of the enclosures being controllable between at least a first state in which gas within the enclosure is substantially non-conducting and a second state in which the gas within the enclosure forms an electrically conductive plasma. At least one pair of adjacent enclosures in the array is arranged such that configuring the pair of enclosures in the second state results in an electrical connection, between a first electrode associated with one of the enclosures of the pair and a second electrode associated with the other enclosure of the pair, through electrically conductive plasma of at least one of the enclosures of the pair. The reconfigurable antenna in an illustrative embodiment is operable in a plurality of different modes of operation by altering, from mode to mode, which of the enclosures are configured in the first state and which of the enclosures are configured in the second state.